Potential consumer exposure to respirable particles and TiO 2 due to the use of eyebrow powders

Background Cosmetic powders contain numerous components, including titanium dioxide (TiO 2 ), which is classified as possibly carcinogenic to humans (Group 2B). However, little is known about potential inhalation exposures to particles that are released during cosmetic powder applications. Methods We realistically simulated the application of five different eyebrow powders using a mannequin and then determined concentrations of total suspended particles (TSP), PM 10 , and PM 4 fractions of particles that would be inhaled during powder application. We determined the size and shape of particles in the original powders and released particles, as well as their TiO 2 concentrations and Ti content of individual particles. Results The application of eyebrow powders resulted in the release and inhalation of airborne particles at concentrations ranging from 21.2 to 277.3 µg/m 3 , depending on the particle fraction and the powder. The concentrations of TiO 2 in PM 4 and PM 10 samples reached 2.7 µg/m 3 and 9.3 µg/m 3 , respectively. The concentration of TiO 2 in airborne particle fractions was proportional to the presence of TiO 2 in the bulk powder. Conclusion The application of eyebrow powders results in user exposures to respirable PM 4 and PM 10 particles, including those containing TiO 2 . This information should be of interest to stakeholders concerned about inhalation exposure to TiO 2 .